Field of the Invention
The disclosure relates to an insulator in a laminated structure of an electroconductor, an insulator, and a semiconductor of a photoelectric conversion apparatus.
Description of the Related Art
A photoelectric conversion apparatus typified by a complementary metal oxide semiconductor (CMOS) image sensor is provided with a photoelectric conversion section and a signal processing section for processing signals from the photoelectric conversion section. The photoelectric conversion section can be constituted by a plurality of photoelectric conversion units each containing a metal-oxide-semiconductor field-effect-transistor (MOSFET).
Japanese Patent Laid-Open Nos. 2007-317741 and 2010-056515 disclose using a nitrided gate insulating film for the MOSFET of the photoelectric conversion unit. By the use of the nitrided gate insulating film, the dielectric constant thereof can be made higher than that of a gate insulating film containing silicon oxide formed by a general thermal oxidation method and the photoelectric conversion section can be operated well while reducing a leakage current.
However, when the nitrided gate insulating film is used as in Japanese Patent Laid-Open Nos. 2007-317741 and 2010-056515, the photoelectric conversion section has not been able to achieve sufficient performance in some cases. Thus, it is an object of the disclosure to improve the performance of the photoelectric conversion section.